Objective: To explore whether resveratrol can postpone the fibrosis associated with diabetic cardiomyopathy (DCM) by modulating the mitochondrial autophagy response through the AMPK/SIRT1-mediated IRE1α/PINK signaling pathway.
Methods: A DCM mouse model was established using a high-sugar high-fat diet and streptozotocin. Resveratrol was administered to a subset of the DCM mouse models for comparison. Echocardiography, Masson staining, TNUEL assay, and transmission electron microscopy were employed to evaluate the cardiac status, myocardial fibrosis, myocardial cell apoptosis, and morphological changes of myocardial cells and their internal mitochondria in each group of mice. Western blot staining was performed on myocardial tissues to assess the protein expression levels of p-AMPK, SIRT1, SIRT3, p22, GP91, p-IRE1α, XBP1s PINK, Parkin, LC3I, and Beclin. Mouse myocardial cells were cultured in vitro and intervened with a high-sugar high-fat diet, resveratrol, and GSK690693 (an AMPK inhibitor) to observe the protein expression levels of p-AMPK, p22, XBP1s, and PINK in mouse myocardial cells in each group.
Results: Results from echocardiography, Masson staining, TNUEL assay, and transmission electron microscopy showed that resveratrol administration alleviated cardiac damage, myocardial fibrosis, myocardial cell apoptosis, and mitochondrial autophagy in DCM mice. Resveratrol administration promoted the expression of phosphorylated AMP-activated protein kinase (p-AMPK), sirtuin 1 (SIRT1), and sirtuin 3 (SIRT3) in the myocardial tissue of mice, while lowering the elevated protein expression levels of p22 subunit (p22), guanine nucleotide-binding protein q polypeptide 1 (GP91), phosphorylated inositol-requiring enzyme 1 alpha (p-IRE1α), X-box binding protein 1 spliced form (XBP1s), PTEN-induced putative kinase 1 (PINK), Parkin, microtubule-associated proteins light chain 3 isoform I (LC3I), and Beclin (Bcl-2 interacting protein) caused by DCM. GSK690693 (an AMPK inhibitor) suppressed the expression of p-AMPK, SIRT1, and SIRT3 and enhanced the protein expression of p22, XBP1s, and PINK.
Conclusion: Resveratrol postpones dilated cardiomyopathy fibrosis by regulating the mitochondrial autophagy response through the AMP-activated protein kinase (AMPK)/silent mating type information regulation 2 homolog 1 (SIRT1)-mediated inositol-requiring enzyme 1 alpha (IRE1α)/PTEN-induced putative kinase 1 (PINK) signaling pathway.